The present invention relates generally to parameter prediction and in particular to closed loop control and built-in test (BIT) of components using a reduced order model (ROM).
Complex systems, such as those implemented onboard aircraft, often include parameters that may not be sensed by physical sensors of the system. For example, air-conditioning packs may not have sensor readings for parameters such as Air Cycle Machine (ACM) rotational speed. It may be possible to sense these parameters with physical sensors, but at added cost and complexity. Other parameters, such as compressor or fan surge margin, may not be measurable by physical sensors at all. Even though these parameters are not sensed, knowledge of the parameters may be useful for protective or backup control modes. Adding additional sensors, however, contributes to higher cost and complexity, as well as reoccurring cost to the product. It is desirable to implement a low-cost method of determining characteristics of an environment not directly sensed by physical sensors.